[rules-users] Parse bug in predicate constraints?

[Edson Tirelli]

   Justine,

   It shouldn't be space sensitive. Where are you inserting the space 
that is giving you the error? I see your line bellow is missing a ')' in 
the end, but maybe it was a mistake when you wrote the e-mail... so, 
could you please clarify?

   In trunk the syntax was simplified to almost what you asked for. In 
trunk you can write:

rule "test"
    when
       valObj : MyValuesObject(a:aVal, b:bVal, c:cVal,
                                               (a < (1/780)*(b+c)),
                                               ((b + c) > 500000) )
    then
        System.out.println("Alert condition met on obj:" + valObj);
end

   You can break lines as you wish, but the predicates must be inside 
the fact scope.

    Hope it helps,
 
    Edson.



Justine Hlista wrote:

> Should predicate constraints be sensitive to whitespace?? I have the 
> following rule with a predicate constraint:
> rule "test"
>     when
>         valObj : MyValuesObject(a:aVal, b:bVal, c:cVal -> 
> ((a.intValue() <  (1/780) * (b.intValue() + c.intValue()) && 
> (b.intValue() + c.intValue()) > 500000)
>     then
>         System.out.println("Alert condition met on obj:" + valObj);
> end
>
> Inserting whitespace into the predicate results in the following 
> exception:
>
> org.drools.rule.InvalidRulePackage: unknown:155:85 mismatched token: 
> [@1723,5226:5227='\r\n',<4>,155:85]; expecting type ')'
> unknown:156:28 mismatched token: [@1752,5256:5256='(',<23>,156:28]; 
> expecting type ')'
>
> If instead I use an eval on the LHS, I can insert whitespace without 
> an exception.
>
> In addition, I would like to know if there are any plans to simplify 
> the syntax for similar types of rules, as the above is extremely 
> unwieldy for the non-expert.
> For instance, I would vastly prefer to write the following:
>
> rule "test"
>     when
>        valObj : MyValuesObject(a:aVal, b:bVal, c:cVal)
>        (a < (1/780)*(b+c))
>        ((b + c) > 500000)
>     then
>         System.out.println("Alert condition met on obj:" + valObj);
> end
>
>
> Also, since everything in rules needs to be an Object, is there any 
> plan to make the operators deal with said Objects? That is, so I do 
> not always have to de-reference with my eval or predicate objects with 
> intValue() or floatValue() or whatever? 
>
> In our application, the user (i.e. not a drools or java expert) will 
> be writing the rules. The current syntax requirements for encoding the 
> above simple rule makes me very nervous about our users ever being 
> able to use the rules effectively.
>
> Thanks,
> Justine
>
>
>
>
>
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>
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-- 
 Edson Tirelli
 Software Engineer - JBoss Rules Core Developer
 Office: +55 11 3124-6000
 Mobile: +55 11 9218-4151
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